Fabricating composite parts, for example a ply-by-ply airplane wing stringer, requires the use of a lay-up tool (also known as a base tool) on which layers of composite pre-preg materials or pre-cure lamina are formed one ply at a time. Once the desired numbers of layers are placed on the base tool, the composite laminate is then removed and placed on a cure tool for final assembly, consolidation, and curing in a curing apparatus, such as an autoclave. Removal of the composite laminate from the base tool can present challenges in that the inherently sticky composite pre-preg materials tend to adhere or stick to the base tool surface. When this occurs, the removal of the composite may require the use of force that can impact the quality of the still uncured composite laminate resulting in a loss of product and increased production times and costs.
In an effort to avoid the issues that can arise during the removal of a composite laminate from a base tool, some fabricators apply the composite plies directly onto a cure tool, thus avoiding the need for removal of the pre-cure composite lamina before the curing operation is performed. Unfortunately, cure tools are generally much heavier than base tools making it difficult to relocate the cure tool with the attached composite laminate from the layup assembly area to the curing apparatus. Cure tools are also typically more expensive and in limited supply as compared to base tools, which therefore greatly increases the fabrication time and costs.
There has been limited success with use of release films applied to the base tool because these films have inherently have low tack properties and do not provide a stable and secure surface for the layup of the plies of composite pre-preg material. This can result in slower than desired laydown rates and an increase in scrapped parts.
Accordingly, there is a need for systems and methods of laying up composite plies over a base tool that allows each ply to be deformed as it is applied to the tool in order to closely conform the ply to the tool contours while the ply remains accurately positioned. Once a composite lamina is formed on the base tool, the final composite laminate can be removed from the base tool without damage.